Method for simultaneously transporting liquids and solids through a common pipeline



Feb- 7, 1967 DARCY A. SHOCK ETAL METHOD FOR SIMULTANEOUSLY TRANSPORTING LIQUIDE AND SOLIDS THROUGH A COMMON PIPELINE Filed Nov. 19, 1964 United States Patent O 3,302,977 METHOD FOR SIMULTANEOUSLY TRANSPORT- ING LlQUIDS AND SOLIDS THROUGH A COMMON PIPELINE DArcy A. Shock and .lohn M. Crawford, Ponca City, Olrla., assignors to Continental Oil Company, Ponca City, Okla., a corporation of Delaware Filed Nov. 19, 1964, Ser. No. 412,544 13 Claims. (Cl. 302-44) This invention relates to a process for simultaneously transporting liquids and solids through a common pipeline. More particularly, the present invention relates to methods for treating solid materials to improve the susceptibility of such materials to simultaneous transport with a liquid through a common pipeline.

It is wellknown that materials which can be pumped can usually be much more economically transported from one location to another by means of a pipeline than by rail, ship or motor truck. Moreover, the geographic locations of the sources of some types of raw materials further increase the feasibility of pipeline transport as compared to transport by various types of motor or engine driven vehicles since the accessibility of the location of the raw materials renders the provision of access roads, rail lines or ship channels extremely expensive and, in some instances, totally infeasible.

The present invention comprises a process for simultaneously transporting a liquid and particles of a solid material through a common pipeline. The invention -is more specifically directed to a novel method of pretreating solid materials which it is desired to transport through a pipeline so as to render such solid materials more compatible with a selected liquid used as a carrier for moving the solid materials through the pipeline. As an incident to the solid pretreatment techniques prescribed by the invention, certain additional novel procedures are required to reclaim the solids in their original form after separation of the treated solids from the liquid at the `destination of one or the other of the materials which are moved through the pipeline.

Broadly, the present invention comprises the steps of initially adjusting the density or specific gravity of the solid particles by incorporating in such particles another material which changes the bulk density of the solid so as to more nearly conform to the density of a liquid which is to be transported simultaneously with such solids, then form-ing a slurry or suspension of such treated solids in the liquid, pumping both the liquid and solid through a pipeline to their respective destinations, and finally, separating the solids from the liquid, and if desired, restoring the solid to its original state by removal of the density modifying agent. By adjusting the bulk density of the solid particles to conform relatively closely to the density of the liquid, the buoyant effect of the liquid on the solids is increased and the settling rates of the solid particles in the liquid during transport is substantially reduced. To the extent that the bulk density of the solid particles can be made identical to that of the transported liquid, the problem of solid settling in the pipeline becomes non-existent.

The solid particle pretreatment technique which has been broadly described as incorporating in the solid another material which results in an increase or decrease of the overall or bulk density of the solid mass can be practiced by two general methods. The more suitable procedure will more frequently be that of incorporating air into the solid particles by entrapment -of encapsulation so that the specific gravity or density of the overall bulk of the particle is decreased. In the second approach to the problem, the solid particles are integrated with other solids of different density so as to adjust the overall or 3,302,977 Patented Feb. 7, 1967 ICC bulk density of the particles in the desired direction. In

general, these procedures constitute an entirely different v approach to the problem of solid settling than those which have been heretofore proposed in that, rather than reducing the surface area of the solid particles to reduce settling rate, some increase in surface area will usually occur as the result of the incorporation of air or other material into the solid particles to reduce the bulk density thereof.

In one embodiment of the invention, more nearly matching solid and liquid densities are obtained by varying the density or specific gravity of the liquid in addition to changing the density of the solid to be transported therewith in the manner hereinbefore described. It is also within the purview of the invention to enhance the beneficial effect of preadjusting the density of the solid particles by varying the viscosity of the liquid so as to further reduce the rate at which the solid particles may settle out of the liquid during transport.

From the foregoing description of the invention, it will have become apparent that it is a major object of the present invention to provide an improved method for simultaneously transporting solid particulate materials and a liquid or liquids through a common pipeline.

A more specific object of the invention is to provide a new te-chnique for reducing the rate at which solids will settle or gravitate through a liquid when such solids and liquids are simultaneously moved through a common pipeline.

Another object of the present invention is to provide procedures by which the bulk density of solids can ber adjusted in a desirable fashion preparatory to simultaneously transporting such solids with a liquid through a common pipeline.

Another object of the invention is to pretreat solid particles in a manner which permits the benefit of specific gravity adjustment of the solids to be obtained preparatory to moving such solids through a pipeline simultaneously with one or more liquids.

A further object of the invention is to permit solids and liquids .to be transported simultaneously through a common pipeline with less resistance to flow offered by the mixture of such materials.

In addition to the foregoing described objects and advantages, additional objects and advantages will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawing which schematically illustrates apparatus which can be utilized in the practice of the process of the invention.

Before referring to the drawing which schematically illustrates an exemplary system which can be used in the practice of the invention, it is believed that a brief consideration of some general aspects of the invention will be helpful. As hereinbefore indicated, one of the major problems encountered in attempts to simultaneously transport liquids and solids in a common pipeline is the tendency, in most instances, of the solids to settle or gravitate in the liquid, and, by accumulations at joints and couplings, to cause stoppage of flow, or by frictional resistance, to impose pumping requirements which cannot be economically met. Two major factors are critical in the occurrence of the settling problem. These are the speed of travel of the transported materials through the pipeline, and the difference in density between the transported liquid and the solid entrained therein. It has been previously recognized that rates of movement of the materials through the pipeline which produce turbulent flow are to be preferred since the turbulence engendered in the mixture tends, by mechanical agitation, to prevent settling of the solids.

It is to the second of these factors, i.e., the difference in density, that the present invention is addressed. In general, the primary object of the invention is to narrow or reduce the difference in density which exists between the liquid and solid materials being transported. The range of liquid densities is, in general, substantially lower than that characteristic of solid materials. The specific gravity or density of water is, of course, approximately 1, and the specific gravities of liquid hydrocarbons range from about 0.5 to about 0.9, with the more frequently occurring range extending from about 0.7 to about 0.8. The specific gravities of most solids, on the other hand, range from about 1 to about 3. Some metallic ores are considerably higher in density with certain mercury, lead and ion ores ranging from about 4 to about 9 in specific gravity.

From the foregoing considerations, it is seen that the scope of the problem of density matching can be reduced, in most instances, to a matte-r of reducing the density of the solid which it is desired to transport to the point where its bulk density conforms to, or approaches, the specific gravity of the liquid to be transported. Where circumstances permit, some discretion can be exercised in the selection of a liquid so as to make the required reduction in the density of the solid particles smalle-r. In general, solutions of various salts or other soluble solids can be prepared which have specific gravities ranging between 1 and 2, and where some useful object can be accomplished by the use of such solutions as the transporting liquid, less reduction in solid particle density will be required to achieve the extent of matching desired. Examples of such solutions and their specific gravities are 30 percent aqueous solution of NaCl, specific gravity 1.2; 18 percent aqueous solution of Na2CO3, specific gravity 1.14; 30 percent aqueous solution of NaOH, specific gravity 1.3; 50 percent aqueous solution of NaOH, specific gravity 1.5; 40 percent aqueous solution of NaNO3, specific gravity 1.3; 24 percent aqueous solution of Na2SO4, specific gravity 1.23; 70 percent aqueous solution of SnCl4, specific gravity 1.97; 50 percent aqueous solution of sucrose, specific gravity 1.22; 85 percent aqueous solution of sucrose, specific gravity 1.44; 50 percent aqueous solution H2SO4, specific gravity 1.39; 98 percent aqueous solution H2504, 1.83 and 64 percent aqueous solution of NH4NO3, specific gravity 1.3.

In one of the more widely used, and easily practiced embodiments of the present invention, the density of solid particles to be simultaneously transported with a liquid is adjusted downwardly by incorporating into the solid particles, void spaces which contain entrapped air. A number of techniques are known to the art for incorporating air in solid materials, but one of the most Widely used of these, and one which is preferred in the practice of the present invention, particularly in instances where the solid materials to be transported are organic materials such as bromoacetic acid, ethyl carbamate, stearic acid, stearonitrite, octadecanamide, N-phenylmorpholine, palmitic acid, phenyl diethanolamine, myristic acid, glucose pentapalmitate, phenoxyacetic acid, octadecylamine, p-dichlorobenzene, lauric acid and hydroxyacetic acid, is that of producing a foam in which contained, or completely enclosed, cells are formed in the body of solid material. The total amount of void space, or the porosity, of such foamed solids can frequently be adjusted by techniques presently understood by those skilled in the art and, in this manner, the bulk density of the foamed solid can be adjusted so that the solid particles can be custom lmatched to the liquid with which they are to be transported.

An example of a material which can be foamed in the described manner and which is particularly significant insofar as pipeline transportation is concerned is sulfur. The sulfur can be easily foamed by heating the sulfur to a molten state and forcing air through the molten sulfur to form a froth. After the sulfur is foamed, it can be crushed and reduced to a desired particle size, usually crushing.

4 from about 4 to about 200 mesh. The foamed sulfur particles are then slurried with a suitable material, such as a hydrocarbon prior to pumping both materials through a common pipeline to their respective destinations.

An alternate embodiment of the present invention comprises the entrapment of air in the solid materials to be transported by initially powdering the solid, then very lightly forming the powder into larger particles of relatively small net solid volume with entrapped air enclosed therein, then enclosing such agglomerated particles in a suitable coating material to retain the particle shape and the entrapped air during the transport of the particles. Stated differently, this technique comprises making pellets which are characterized in having a bulk density equal, or very close, to the transported liquid density, which pellets include a hard outer coating with lightly compacted powder and air contained in the interior thereof. The coating material employed may, in some instances, be the same material as the solid which is powdered at the outset of the process. In other instances, it will be desirable to coat the lightly compacted powder with some other type of material which may later be separated therefrom after the solid pellets have been recovered from the liquid at the destination of one or the other of the transported materials. As a specific example of this technique, naphthale-ne may be powdered and lightly formed into generally spherical particles containing about 44 percent Void space and having a bulk or overall specific gravity of about 0.68. These pellets can then be coated with a thin impermeable coating of starch or glucose so that the final bulk specific gravity of the coated particle is about 0.7. The specific gravity of the naphthalene, which is 1.145 prior to treatment, has thus been adjusted downwardly to the point where it can be effectively transported with hydrocarbon solvents such as gasoline and kerosene. Moreover, the carbohydrate coating prevents solution of the naphthalene in the hydrocarbon carrier liquid. At the destination of the naphthalene, the coating can be easily removed and the naphthalene recovered by contacting the particle-s with water in which the glucose or starch is soluble but the naphthalene is not. The starch or glucose coating can be easily applied in this procedure by techniques similar to those employed in sugar coating the gelatin centers of jelly beans.

Yet another embodiment of the present invention comprises encapsulating or coating the solid with -a plastic material such as wax or synthetic thermoplastic resins which either entraps sufficient air in the plastic shell to match the density of the particle thus formed to the density of the transported liquid, or which is used in a foamed state and thus contains in the cells of the foam enough air to achieve such density matching. In this instance, it will usually be desirable after separating the plastic coated particles from the liquid at the destination of the materials to recover the plastic coating material from the enclosed solids. One manner in which this type of integration may be accomplished is as follows. The particles to be coated are first formed in irregular shapes by a comminuting procedure such as ball milling or The irregularly shaped particles are then lightly contacted with a relatively viscous coating material, such as wax, while the coating material is maintained at a temperature just above the melting point. In this state, the coating material will not ow into voids and cracks in solid particles, but will bridge across these irregularities and entrap air therein. It is especially desirable to utilize a molten coating material which will undergo a substantial amount of contraction upon cooling and solidifying.

Instead of coating the slid particles with a foamed plastic or a plastic which is applied in a way to entrap or enclose air in the interior thereof, a slightly modified procedure which can be desirably employed, in some instan-ces, is the application of the solid material to small particles of foamed plastic. In other words, in this instance, the solid material to be transported is applied as a coating surrounding the foamed plastic material or around a plastic bubble so that the density of the pellet which is formed is matched with or brought more closely to that of `the liquid with which the solid is to be transported. Solvent extraction, crushing, screening or filtration techniques can be used for separating the foamed plastic density adjusting agent from the primary solid after the pellets have been separated from the liquid at the terminus of the transporting pipeline. An example of this type of density adjustment is that of coating foamed polystyrene or polyurethane with a coating of sodium sulfate decahydrate (Na2SO4lOH2O), commonly known as Glaubers salt. The polystyrene will have a bulk density in the foamed state of about 0.05 gram/ cc. The sodium sulfate, on the other hand, has a density of about 1.4 grams/ cc. Thus, by applying a relatively thick coating of the sodium sulfate to the polystyrene the overall or bulk density of the coated particles may be brought into the range where the particles can be effectively transported with various hydrocarbon carrier liquids.

As hereinbefore mentioned, in nearly all of the instances where density adjustment is accomplished through the use of some type of foaming procedure, it will be possible to control to a certain extent the void space within each of the particles or pellets which is formed so as to be able to control as desired the bulk density of the particles. It is thus possible, by either controlling the foaming technique, or by controlling the amount `of foamed plastic used in conjunction with the material to be transported, to selectively adjust the density of the product particles, and thereby obtain a wider choice of liquid materials with which such solids can be transported without substantial interference by the settling problem hereinbefore described. Adjustment to variations in liquid viscosity resulting from seasonal temperature variations can also be more easily accomplished by virtue of the control over bulk Idensity which can be realized through the practice of the foregoing techniques.

Let it be supposed, for example, that in an area in which heavy petrochemical industrialization exists, pipelines are available for transporting materials to remote locations, and that materials on hand in the various petrochemical and petroleum refining facilities include kerosene, gasoline, various alcohols, crude oil, polystyrene, caustic, spent sulfuric acid and water. ln a remote area accessible by pipeline for the petrochemical complex, facilities exist for marketing the kerosene and the polystyrene. If sodium sulfate can also be disposed of at the destination of these materials, the polystyrene can be formed to any desired density of from about 1 to about 6 lbs/cubic foot by controlled foaming techniques presently in use. The caustic and spend sulfuric acid can be reacted to form Na2SO4-lOH2O- The latter material has a density of about 87 lbs/cubic foot. Kerosene has a density of about 50 lbs/cubic foot. The foamed polystyrene can therefore be successfully transported in the kerosene by applying a thick coating of the sodium sulfate to particles of the polystyrene so as to match the bulk density of the particles to the density of the kerosene. It will be perceived that if the polystyrene is foamed to provide a density of 5 lbs/cubic foot, the volume of sodium sulfate used in the coating should be slightly greater than the volume of foamed polystyrene lwhich is used in the coated particle. If, on the other hand, water having a density of 62 lbs/cubic foot is the most convenient carrie-r liquid to be used and there is a -demand for paraffin wax (density about 60 lbs/cubic foot) at the destination, foamed sulfur or sodium sulfate can be coated with wax and shipped through the pipeline with water.

Yet another embodiment of the present invention comprises the adjustment of solid particle density by the inclusion or incorporation in the solid material which it is desired to transport of another solid material which irnparts to the composite solid particles or pellets, a bulk density which is more nearly matched to that of the transported liquid. Thus, rather than any dependency upon the entrapment or inclusion of air being involved in the particle density adjustment, the density of the solid modifying material is relied upon to effect the adjustment in bulk density. An example of this procedure for bulk density adjustment is the coating of some of the heavier metallic ores, such as hematite (Fe2O3), having a density of 4.9 to 5.3 with certain organic thermosetting resins, such as melamine, having a specific gravity of 1.5. If the melamine coating of relatively small ore particles is made sufficiently thick to reduce the bulk density of the coated particles to about 2.0 or lower, the pellets thus formed may be transported in a solution, such las a saturated sucrose solution or a saturated stannous chloride solution which have densities of 1.45 and 1.97, respectively, without sufficient density difference existing to result in an unacceptably high rate of settling of the pellets in such solution.

The manner in which the present invention is practiced may be better understood by referring to the accompanying drawing which schematically illustrates an apparatus or system which can be employed in typical situations in which it is desired to simultaneously transport a solid material with a liquid material having a density which differs substantially from that of the solid. A pipeline 10 through which the solid and liquid materials are to be simultaneously transported is connected to a suitable pump 12 which has sufficient capacity to force the mixed materials through the pipeline. Suitable apparatus for foaming the solid material is provided adjacent the pipeline 10 at the point of origin of the solid and is designated by reference character 14. This apparatus may be, in the case of :some types-of organic plastics, a suitable enclosure in which the plastics may be foamed in place by techniques well-known in the art, or may be a vat in which air or other suitable gas is blown through a viscous material which can later set up to a solid state with air encapsulated therein to form a rigid foam.

The foam produced in apparatus 14 is passed on a conveyor 16 to a suitable cornminuting or pulverizing machine 13 where the lsolid material is reduced to a relatively small particle size. From the comminuting machine 18, the foamed solid is permitted to gravitate through a hopper 2d into a suitable coating apparatus which can optionally be used to coat the foamed solid particles with Aanother material, or which, in some instances, will be inactivated to permit the foamed solid particles to be passed therethrough without coating with another solid material if such is preferred. The coating apparatus may take the form of a rotating drum 22 having spray nozzles (not shown) positioned around the periphery thereof which spray the tumbling solid particles contained in the spray coating drum with t-he coating material. A suitable reservoir or tank for containing a liquid coating material is schematically illustrated by reference character 24 and can supply a material to be coated upon the foamed particles to the spray coating apparatus 22 when a valve 25 is opened.

From the spray coating drum 22, the `solid particles which have been passed therethrough are permitted to gravitate into a mixing valve 26 which functions to thoroughly mix the solid particles with the liquid which is to be simultaneously transported therewith through the pipeline 10. Suicient time lapse will have been provided from the time the foamed particles are coated until they reach the mixing valve 26 to permit the coating material thereon to set up to a hardened state and thus resist removal by contact in the mixing valve with the liquid from the pipeline 10. Liquid from the pipeline 1t) may be circulated through the mixing valve 26 through a by-pass conduit 28.

In the mixing valve 2.6, a pumpable slurry or suspension of the solid particles in the transported liquid is produced, and is passed from the mixing valve into the pipeline 10. In some situations, it may be desirable to divert the entire stream of liquid owing in the pipeline through a mixing valve or other suitable mixing device for purposes of forming the slurry so that the slurry composition and physical properties can be more precisely controlled than can be the case Where only a portion of the liquid stream from the pipeline is diverted through the mixing Valve.

By reason of the entrapment of air in the foamed particles, these particles have a reduced bulk density over that which characterizes the unfoarned parent material. In some instances, such as the pipeline transport of sulfur, the solids settling problem hereinbefore described can be obviated by merely foaming the materials to be transported, and no coating of the foamed particles will then be effected in the spray coating drum 22. In other situations, Where the solid material which is to be transported is not, per se, susceptible to foaming with consequent entrapment of air, it will often be possible to apply this material as a solid coating around small particles of a selected foamed material, such as some of the organic plastic materials which are susceptible to foaming. In this case, the foamed particles are produced in the foaming apparatus 14 and solid pulverizer 18 and are then passed into the spray coating drum 22 Where the material to be transported is applied to such foalmed solid particles as a thin solid coating surrounding the foamed particles. The bulk density of the pellets or particles thus formed is substantially lower than the original density of the pure coating material (which is actually the solid to be transported) so that the composite particles have a bulk density which closely approaches the density of the transporting liquid.

One other possible use of the system thus far described may also be cited. This is the use in which solid particles which are not susceptible to foaming are passed directly into the hopper' 20 and into the spray coating drum 21.. These particles can be particles which are of sufficiently high density to pose a problem of simultaneous transport with certain liquids. In such event, it Will frequently be possible to coat the solid particles with a relatively low density organic resin or other material which sets up to a hardened state, and is characterized in having a density lower than, or closely approaching, that of the liquid in which the unfoamed solid material is to be transported. After coating the high density `solid particles with a low density coating material, a slurry can be formed in which the density of the composite solid particles fairly closely approaches that of the carrier liquid with the result that relatively slow settling of the solid particles occurs as the mixture is moved through a pipeline.

After the slurry or suspension has been formed in the mixing valve 26 and introduced to the pipeline l0, the mixture is moved through the pipeline over the transport distance to the destination of either or both of the solid and liquid materials being transported. At such destination, the solids are removed from the liquid by a suitable solids separator designated by reference character 30. Such separation may be accomplished by ltration, centrifugation or other conventional procedures for removing entrained solids from a liquid carrier. The liquids may then be passed on through a pipeline 32 to a different destination or, in some instances, may be desirably recycled to the point of origin of the materials for reutilization in subsequent transport of solids.

The solid pellets or pa-rticles removed by the separator 30 can be passed through a chute 34 to a solvent extractor 36 which functions to remove any coating material which has been used to coat the base or nucleus solid particles. Of course, in instances where the solid particles transported With the liquid have not been coated, but where foaming of the material alone has been relied upon for density matching, the solvent extractor 36 is not utilized, and the materials may be passed directly to a solids drying device 38 by way of a chute 40. A suitable two-way valve 42 is provided for channeling the solids into either the solvent extractor 36 or the solids dryer 38 as may be dictated by the circumstances. The solids dryer 3S removes any residu-al liquid which may be carried on the solids as a result of the simultaneous liquid transport.

When the solvent extractor 36 is employed for the purpose of removing the coating material from the pellets, a suitable solvent for the coating material is circulated through the extractor and preferentially dissolves the coating. The internal solid which has been coated in the spray coating drum 22 is not dissolved and gravitates to the bottom of the extractor. The solution of solvent and coating material is then passed through the conduit t4 to a solvent-coating separator 46 Where the coating material is separated out and passed via conduit 48 to a coating material storage drum 5t). The solvent-coating separator employed can be a fractional distillation column or any other device suitable for separating two lmiscible liquids. The separated solvent is recycled 4through the conduit 45 to the solvent extractor 36. If desired, the coating material may be recycled from the storage drum 5t) through a `sui-table conduit (not shown) to the coating material tank 24 in instances Where the coating material is not the primary material which it has been the object of the invention to transport. Allternatively, the coating material can, of course, be used in the manner hereinbefore described for transporting the same or a different solid through the same pipeline in the reverse direction.

The solids removed in the solvent extractor 36 are passed to the solids dryer 38 where residual solvent is removed by a suitable drying technique. From the solids dryer 38, the solid particles are carried by a conveyor 52 to a solids storage dump 54 for subsequent utilization or, if this solid has been the secondary solid used for density modication, this solid may also be recycled to the point of origin of the solid-liquid transport for reutilization.

It will be understood that the schematic portrayal in the accompanying drawing of one system which may be employed for practicing certain embodiments of the present invention is not -to be considered as limiting with respect to various types of apparatus which will be used for effecting other results in conformity with other embodiments of the invention as hereinbefore described. Thus, different and more sophisticated apparatus will be required for forming composite pellets having lightly packed, powdered solid particles on the interior thereof with a hardened coating of material enclosing such lightly packed solids in the manner hereinbefore described. It will be further apparent that different types of separatory and recovery apparatus may be employed at the destination of the solids and/or liquids than that which is portrayed in the accompanying drawing. The drawing does serve, nevertheless, to illustrate the basic concepts which underlie the present invention, and to make clear the manner in which all embodiments of the invention are practiced.

From the foregoing description of the invention, it will have become apparent that the present invention provides a novel and highly useful procedure for improving the ease with which a variety of solids may be simultaneously transported With many different types of liquids through a common pipeline. The approach which is taken of adjusting the bulk density of the solid particles to more nearly match that of the transporting liquid is believed to be a novel approach to the problem of undesirable settling of solids in the transporting pipeline. Although the incorporation or integration of one type of solid with another material for the purpose of modifying in a beneficial direction the density of the first-mentioned solid has as its primary object, the Imatching of the bulk density of the solid particles so for-med with that of the transporting liquid, it will be readily seen that certain other incidental advantages accrue from the practice of this technique. As examples of such incidental advantages may be mentioned the ability to transport two different types of solids with the transporting liquid, Ithe .ability to protect or insulate the encapsulated or enclosed solid from contact with the liquid in which it is being transported, and the ability, as a result of reduction in total surface area through the foaming technique, to reduce corrosion problems and the tendency of the solid to dissolve in the transported liquid.

Although certain specific embodiments of the present invention have been hereinbefore illustrated and described, it is to be understood that other embodiments involving slight innovations in the described procedures, but continuing to rely upon the basic principles hereinbefore enunciated, may be employed without change in the basic principles and conceptions which have been utilized in the described embodiments. insofar, therefore, as such innovations and modifications do not entail a departure from the basic concepts which underlie and form the basis for this invention, such innovations and modifications are deemed to 4be circumscribed by the spirit and scope of the invention except as the same may be necessarily limited by the appended claims or reasonable equivalents thereof.

What is claimed is:

1. The method of simultaneously transporting a solid and liquid through a common pipeline comprising:

integrating at least one additional material selected from the group consisting of air and a second solid having a lower density than said rst solid with said solid to produce a composite solid having a bulk density substantially closer to the density of said liquid than the density of said solid prior to the integration of said additional material;

mixing said liquid and composite solid; and

pumping said mixture through said pipeline.

2. The method defined in claim 1 wherein said additional material is entrapped air.

3. The method defined in claim 1 wherein said additional material is another solid after being integrated with said rst-mentioned solid.

4. The method dened in claim 2 wherein the air is integrated with said solid by foaming said solid.

5. The method deiined in claim 2 wherein the air is integrated with said solid by comminuting said solid to a powder; and

enclosing said powder and air in a coating of a second solid material to form pellets having a bulk density closer to the density of said liquid than the density of said rst-mentioned solid.

6. The method defined in claim 2 wherein the air is integrated with said solid by incorporating a second solid in a foamed state in said rst solid.

7. The method dened in claim 4 wherein said solid is sulfur.

8. The method dened in claim 3 wherein said other solid is integrated with said first-mentioned solid by depositing said other solid around said rst-mentioned solid as a liquid coating and then permitting said other solid to set up to a hardened state.

9. The method of simultaneously transporting a solid and a liquid having a lower density than said solid through a common pipeline comprising:

physically integrating at least one additional material selected from the group consisting of air and a second solid having a lower density than said rst solid with particles of said solid to produce composite particles having a lower bulk density than the density of said solid before said physical integration;

intimately mixing said composite particles with said liquid to form a pumpable slurry;

moving said slurry through said pipeline; and

recovering said composite particles from said liquid.

10. The method dened in claim 8 and further characterized to include the step of separating said additional material from said solid particles after recovering said composite particles from said liquid.

11. The method of solids treatment to adapt a solid for simultaneous transport with a liquid through a common pipeline which comprises incorporating in particles of said solid another material selected from the group consisting of air and a second solid having a density sufciently diierent from that of rst said solid to impart to the particles in which said other material is incorporated, a density substantially closer to that of said liquid than the original density of said solid prior to such incorporation.

12. The method defined in claim 11 wherein said other material is air.

13. The method defined in claim 11 wherein said other material is a second solid.

References Cited by the Examiner UNITED STATES PATENTS 1,091,251 3/1914 Stauffer 302-66 2,128,913 9/1938 Burk 302-66 2,610,899 9/1952 Cross 302-66 2,610,900 9/ 1952 Cross 302-66 2,610,901 9/1952 Cross 302-66 2,798,772 7/1957 Redclay 302-14 3,019,059 1/ 1962 McMurtrie 302-66 3,206,256 9/ 1965 Scott 302-66 FOREIGN PATENTS 939,018 8/1955 Germany. 711,105 6/1954 Great Britain.

ANDRES H. NIELSEN, Primary Examiner. 

1. THE METHOD OF SIMULTANEOUSLY TRANSPORTING A SOLID AND LIQUID THROUGH A COMMON PIPELINE COMPRISING: INTEGRATING AT LEAST ONE ADDITIONAL MATERIAL SELECTED FROM THE GROUP CONSISTING OF AIR AND A SECOND SOLID HAVING A LOWER DENSITY THAN SAID FIRST SOLID WITH SAID SOLID TO PRODUCE A COMPOSITE SOLID HAVING A BULK DENSITY SUBSTANTIALLY CLOSER TO THE DENSITY OF SAID 